Means for driving tube drawing benches



I Dec. 20, 1938. F. KocKs 2,140,633

. I r 5 W fl|||||||||||||||||||||i||||||||||||||||||||||H illll! ||||I|||| MEANS FOR DRIVING TUBE DRAWING BENCHES Filed March 18, 1957 2 sheets-sheet 1 munmnum" Inventor .7 71 0060 .fltome Dec. 20, 1938. KQCKS 2,140,633

' MEANS FOR DRIVING TUBE DRAWING maucmas Filed March 18, 1937 2 Sheets-Sheet 2 l7 l6 1 a Fig.4.

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Inventor y 61/. 5. km!

' adapted to feed the actual working motor.

. as still imperfect.

Patented, 20, 1938 s PATENT OFFICE MEANS FOR DRIVING TUBE DRAWIltlC BENCHES rm. Kooks, Dusseldorf, Germany Application March 18, 1937Q8erial No. 131,710 In Germany March 1'1, i936 Claims. (or 205-4) In order to obtain continuous graduation of control of tube drawing benches it has hitherto been customary to equip the electric driving mechanism with an Illgner set. The Illgner set maybe compared with the Leonard transformer, which consists of a direct current dynamo ordi narily driven by a three-phase current motor and This combination forms a transformer. If this combination is provided with a flywheel which serves for receiving currentimpulses', the transformer is then referred to as an Illgner transformer or set. In view of the fact that the electrical equipment is already more expensive than the remaining portion of the plant, the necessity of using the Illgner .set increases the cost of the whole plant out of all proportion. However not only this circumstance but also'other disadvantageous features attending the aforesaid electric drive, constitute the reason for regarding the customary arrangements for driving tube drawing benches Apart from the low efficiencyv of the Illgner set -(about 65-'70%), this system calls for considerable skill and care on thepart of the operatives-in order to adapt the drawing operation to meet the specific working conditions of the Illgner set. Even the design of the drawing bench itself must be modified to suit these peculiarities of the Illgner set, in order to prevent thevdrawing bench from. being affected as the result, for example, of the ever-present contingency of the motor functioning wrongly. Up

' to the present, this possibility has been taken into consideration by allowing the rack a free run-out beyond its normal end position and arranging at the same time for the rack to move out of gear with the driving pinion and then come to rest. This considerably increases the length of the bench, and thus has an unfavourable effect on the-space occupied.

According to the invention the Illgner set ismade superfluous, the drive being effected -by.

employing a continuously-running three-phase motor which. imparts the forward and return strokes to the rack through a controllable hydraulic gear, the known gear inventedby Thoma being preferred.

The new drive provides simple means for maintaining uniform speeds, both for the return and. for the working strokes, so that, for example, the

2 metres per'second and the return'stroke at about 6 metres per second. The resulting utilization of the speeds according to plan furnishes a large number of finished tubes and therefore a high degree of 'emciency unattainable with the usual inaccurate manual control. Also bearing in mind that the reversing of the direction of movement of the rack is effected much more quickly with hydraulic gear, and more smoothly than in the case of an electric drive of the type hereinbefore referred to, it will be evident that this circumstance also has a beneficial influence on the output. These advantages of the drive also bring others in their train. For example, overstressing of the rack teeth is effectively prevented by the provision, in the hydraulic gear, of a safety or relief valve in the pipe connecting the pump and the actuating unit of the drive. This measure renders superfluous the provision of an over-runfor the rack and-for simultaneously disengaging it from the driving pinion. Reversing the rack can be effected automatically in very simple manner-for example when the Thoma gear referred to is used-by providing stops-adjustable if desired-inbrder to ensure I the maintenance of uniformity in the outward and return strokes of the rack.

nected together by only a pressure-supply pipe and a common tankfor the liquid (oil). Finally, it is pointed out that in actuating the rack by means of two or more pinions, each connected with an actuating unit of the hydraulic gear, the work may be performed with only one pump unit. common to all. This renders a multiplepinion drive particularly-valuable because it enables the total power :to be distributed in equal,

or also intentionally diflerent, proportions, be-

tween the several pinions, since all the actuating units of the hydraulic system are dependent on a common pressure-supply pipe. This last type of drive is particularly advantageous in the event of the reverse failing to come into action. In

such-case the rack comes, when running out,

out of gear with the last pinion. Since this pin- -'ion is no longer exposed to the reaction pressure,

the pressure in the delivery pipe of the hydraulic gear drops and all the oil delivered by the pump passes through the actuating unit allotted to the disengaged, and therefore idling, pinion. Consequently, none ofthe other pinions can any longer transmit power to the rack, and in this manner .the drawing bench is automatically and effectively freed from any excessive stressing.

When the rack is driven by a number of pinions, hydraulic gear may be used comprising a pump unit for each actuating unit, provided all the actuating units be served by a common pressure-pipe.

Several methods of carrying out the invention are diagrammatically illustrated in the accompanying drawings. v

Figure 1 is a diagrammaticrepresentation of a tube drawing bench with operating mechanism- 'nism Referring to Figure 1 of the drawings the three-phase motor I actuates the pinion 3 of the rack 4, through hydraulic gearing 2. 5 is the mandrel. 6 and I denote solenoids or electromagnets which are connected, in the interior of the gearing 2-for example, of the Thoma typewith the rock'able cylinders of the pump and the actuating units. Arranged in the circuits 8 and 9 for the solenoids or electromagnets 6 and 'I are trip switches III and II, actuated by the rack 4 in its opposite end positions. The drawing bench operation is performed by the three-phase motor I imparting the working stroke to the rack 4- and with it the mandrel 5-through the hydraulic gear 2. At the end of the working stroke the rack trips on the switch I I, .by which means the corresponding circuit is completed or broken. Consequently the armature of the solenoid or electromagnet 1 describes an axial movement and thereby swings the motor cylinder body of the gearing 2 into position for reversing the pinion 3. The return stroke of the rack then follows, at the end of which the rack trips the switch I0, thereby causing movement .of the armature of the solenoid or electromagnet 6 and causing, for example,

- the pump cylinder bodyof the gearing 2, to swing into neutral position. At the same time the motor cylinder body must swing-as can also be effected automatically by'suitable relation of the control circuitsinto position for the forward stroke of the rack 4, directly the pump cylinder body has swung back from the neutral position into the working position. So far as the invention is concerned, it is immaterial whether the reversing movements are effected by tilting the two cylinder bodies provided in the Thoma gear, or whether only one of the cylinder bodies is swung into the necessary inclined position.

Figure 2 represents a modification of the construction according to Figure l in which the rack 4'is engaged by two pinions 3 and 3'. In this case the hydraulic gear consists of two actuating members I2 and I3, served by a common pump I4. This pump is driven by the motor I and connected to the actuating members I2 and I3, as

shown. It will be evident that this arrangement ensures exact distribution of motive power between the members I2 and I3, and. therefore be- 2,14o,esa

tween the corresponding pinions 3 and 3'. Should the reversing device according to Figure I fail to act, as hereinbefore described, the rack, in over-running an end position, will come out of gear with either the pinion 3 or the pinion 3',

for example, the first. In consequence, as here- .inbefore described, the hydraulic pressure will only be operative to drive the pinion 3, owing to the low resistance, and the movement of the rack will therefore be arrested.

Figure 3 shows, diagrammatically, the separate arrangement of the pump and actuating units of the hydraulic gear 2. As the result of the two units being connected merely by means of pipes I5, the pump unit and the motor can be set up in anyconvenient place. The manner in which the 2-pinion drive can be arranged in this instance is indicated by dotted lines in Figure 3.

A suitable form of the Thoma drive is illustrated in Figures 4 and 5 and comprises a casing I6 to one end of which the motor I is connected by a flange, the motor being a three-phase motor and serving to drive .a shaft I'I extending within the casing I6, which shaft receives at the end the spherical ball-like ends of connecting rods I8 which directly drive; also through ball-like ends, pistons I9 which respectively reciprocate in the cylindrical borings in a cylinder body 20. The rotary movement of the driving shaft I1 is transmitted by way of a coupling link 2| with universal joints to a stub spindle or axle 22 upon which the cylinder body 20 is fixedly mounted. The said spindle or axle 22 is mounted as in a counterbearing, in a valve disc 23 which is applied against the outer end of the cylinder body 20 and forms the end of a casing 24 for the cylinder body, which casing is mounted on fixed pivots 25 1 disposed in the plane of the end of the driving shaft I I and permitting it to rock in opposite directions. This movement is effected by means of the electromagnet or solenoid 6 which may be mounted on the upper wall of the casing' lIi. If.

the rocking cylinder body casing or frame 24 is inclined relatively to the driving shaft I'I all'the pistons I9 reciprocate when the driving shaft is body casing 24 is connected with a dip pipe 26 immersed in the liquid and leading by a passage 21 to the valve surface of the valve disc 23, the cylinder body and the pistons therein when inclined and rotated will act as a pump. A similar cylinder'body casing 28 and cylinder body 29 is similarly assembled in relation to the driven shaft 30 provided'at the opposite side of the cas-' ing I6. This shaft carries the pinion 3. deliveryside' of the valve disc 23 of the first cylinderbody casing 24 is coupled as by a conduit 3I with the inlet side of the second cylinder body casing so that the liquid forced therein is caused to effect the reciprocation of the pistons 32 in the second cylinder body 29 before being discharged to the liquid in the casing I6 by way of the dip pipe 33. In this manner the driven shaft is caused to rotate. The rocking of the cylinder body casing 28 is effected by the electromagnet the speed of rotation and the work output of the device can be very effectively regulated.

The.

In the arrangement according to the invention with the motor running at a constant speed the working speed of the drawing bench can be smoothly graduated, and the direction of stroke reversed, in contrast to the existing methods oi driving in which the motor actuating the rack gear was itself controlled in respect of speed.

I claim:

1. A tube drawing bench having the mandrel reciprocated by a rack with which is engaged a pinion driven by a prime mover, comprising a constant speed motor serving as the prime mover and a variable hydraulic transmission gear interposed between the motor and the rack pinion for varying the speed and direction of drive of the mandrel, the saidvgear comprising pumps and actuating units that are independent one oi the \other, and fluidcontaining means for completing means aneflecting such adjustment of position under control of the reciprocating elements of the tube drawing bench.

3. A tube drawing bench according to claim 1, I

4. A tube drawing bench having the mandrel.

reciprocated by a rack with which are engaged a multiplicity of pinions, a constant speed motor, a variable hydraulic transmission gear, comprising pumps rotated by the motor and groups of actuating units in number corresponding to the num ber of pinions, each group of actuating units being specific to one pinion, fluid-containing means common to the pumps and the actuating units, and means for varying the speed and direction 01' the drive imparted to the said pinions by the said groups of actuating units, said means being controlled by the reciprocating elements of the'tubedrawing bench.

5. A tube drawing bench according to claim 4, wherein a single pump unit of the variable bydraulic transmission gear operates a number of 

